159 resultados para DCD


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Analisa a viabilidade da substituição da publicação tradicional, em papel, do Diário da Câmara dos Deputados (DCD) por uma versão eletrônica equivalente. A oportunidade e a conveniência da Administração Pública na adoção da publicação eletrônica desse diário são inquiridas à luz dos princípios constitucionais da legalidade, da publicidade e da eficiência. This work evaluates the replaceability of the traditional publishing method, in printed form, of the "Diário da Câmara dos Deputados" (Journal of the Chamber of Deputies), for an equivalent eletronic version. Public administration's opportunity and convenience on the adoption of electronic publishing of this journal are examined through the point of view of the constitutional principles of legality, public visibility and efficiency.

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应用多组分NS方程和频散可控耗散格式(DCD)计算了爆轰驱动激波风洞中反射激波/边界层/接触面的相互作用过程,分析了驱动气体与试验气体在壁面射流作用下的掺混机制及其对风洞试验时间的影响.为了延长风洞的试验时间,提出在风洞贮室内增设环形隔板,以隔离壁面射流,延长风洞试验时间的方法.计算结果表明:环形隔板确实可以限制驱动气体与试验气体的过早掺混,显著增加激波风洞的有效试验时间.

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采用频散可控的耗散格式(DCD),求解Euler方程和一种改进的二阶段化学反应模型,对氢氧反向-正向双爆轰驱动段激波管进行了数值模拟.计算结果表明:当辅驱动段与主驱动段初始压力比小于临界值时,Taylor波仍会出现,但波扇夹角较单一前向爆轰驱动段小,入射激波马赫数衰减率变小;当初始压力比等于临界值时,主驱动段中的Taylor波完全被消除,入射激波马赫数不再衰减.当初始压力比大于临界值时,在主驱动段中能产生过驱动爆轰波,不仅Taylor波被完全消除,而且驱动能力较单一前向爆轰驱动段强

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Pretende verificar a conveniência do armazenamento do Diário da Câmara dos Deputados na Biblioteca Digital da Câmara dos Deputados, com vistas à recuperação do seu conteúdo informacional. A revisão de literatura ressalta a importância do DCD como fonte oficial de publicidade das atividades parlamentares, bem como traz a fundamentação da Biblioteca Digital como repositório institucional e ferramenta importante para apoiar a organização e recuperação da informação bibliográfica na Câmara dos Deputados. O objetivo geral do estudo consistiu em propor um conjunto de metadados de descrição física e temática como requisitos para a organização e representação dos conteúdos informacionais do DCD. A metodologia utilizada permitiu, além do embasamento teórico, a análise dos sistemas de informação da Casa Legislativa, os conteúdos do Diário e, por meio da aplicação de questionário, verificar a visão dos usuários da Coordenação de Relacionamento, Pesquisa e Informação sobre a recuperação das informações do Diário a partir dos sistemas de informação corporativos e locais. Em conclusão constatou-se que a grande maioria das informações publicadas no DCD é passível de recuperação em diversos sistemas de informação, o que, no entanto, não garante a qualidade e tempestividade na recuperação.

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本文应用基元反应模型和频散可控耗散格式(DCD)对氢氧爆轰波进行了二维数值模拟.氢氧混合物的化学反应模型考虑了8种组分20个反应方程式.在处理化学反应引起的刚性问题时采用了时间算子分裂的方法.本文首先对爆轰波数值结果和实验结果进行了对照验证,然后对爆轰波在楔面反射由马赫反射向规则反射转变的过程进行了数值分析,得到了反射转变临界角,并和实验结果及理论分析进行了比较,结果是令人满意的;本文还对爆轰波的多波结构进行了初步的数值分析.

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采用二阶精度频散控制耗散格式(DCD)和8组分20个方程的基元反应模型,对轴对称变截面管道中氢氧爆轰波传播进行数值模拟.结果表明,爆轰波传播至突变截面扩张管道时,由于稀疏波的作用可能会使爆轰波局部熄爆甚至完全熄爆,对于某些敏感度高的反应气体爆轰波可以二次起爆.而在渐变截面扩张管道爆轰波相对不易熄爆.

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本文应用基元反应模型和频散可控耗散格式(DCD)对氢氧爆轰波波后化学反应流场进行了数值模拟,计算中氢氧混合物的化学反应考虑了8种组分20个反应式.在处理化学反应引起的刚性问题时采用了时间算子分裂的方法.分析了爆轰波在楔面上反射由马赫反射向正规反射的转变过程.

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FePt nanoparticles with average size of 9 nm were synthesized using a diblock polymer micellar method combined with plasma treatment. To prevent from oxidation under ambient conditions, immediately after plasma treatment, the FePt nanoparticle arrays were in situ transferred into the film-growth chamber where they were covered by an SiO2 overlayer. A nearly complete transformation of L1(0) FePt was achieved for samples annealed at temperatures above 700 A degrees C. The well control on the FePt stoichiometry and avoidance from surface oxidation largely enhanced the coercivity, and a value as high as 10 kOe was obtained in this study. An evaluation of magnetic interactions was made using the so-called isothermal remanence (IRM) and dc-demagnetization (DCD) remanence curves and Kelly-Henkel plots (Delta M measurement). The Delta M measurement reveals that the resultant FePt nanoparticles exhibit a rather weak interparticle dipolar coupling, and the absence of interparticle exchange interaction suggests no significant particle agglomeration occurred during the post-annealing. Additionally, a slight parallel magnetic anisotropy was also observed. The results indicate the micellar method has a high potential in preparing FePt nanoparticle arrays used for ultrahigh density recording media.

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An (A1As/GaAs/A1As/A1GaAs)/GaAs(001) double-barrier superlattice grown by molecular beam epitaxy (MBE) is studied by combining synchrotron radiation and double-crystal x-ray diffraction (DCD). The intensity of satellite peaks is modulated by the wave function of each sublayer in one superlattice period. Simulated by the x-ray dynamical diffraction theory, it is discovered that the intensity of the satellite peaks situated near the modulating wave node point of each sublayer is very sensitive to the variation of the layer structural parameters, The accurate layer thickness of each sublayer is obtained with an error less than 1 Angstrom. Furthermore, x-ray kinematical diffraction theory is used to explain the modulation phenomenon. (C) 1996 American Institute of Physics.

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通过田间随机区组试验,就缓释尿素对棕壤农田线虫群落产生的影响进行了研究。本试验设置4个处理,(1)普通尿素(U);(2)U+脲酶抑制剂LNS(SRU1);(3)SRU1+硝化抑制剂双氰胺(DCD)(SRU2);(4)SRU1+硝化抑制剂3, 5-二甲基吡唑(DMP)(SRU3)。结果表明,在整个春小麦(Triticum aestivum L.)生育期内,SRU1、SRU2和SRU3处理的土壤脲酶活性低于U处理,且SRU2、SRU3 处理的土壤NH4+-N含量在较长时间内维持在较高水平;4个处理共鉴定土壤线虫39个属,其中Cephalobus和Aphelenchus为优势属,所有处理均以食细菌线虫为优势营养类群;小麦抽穗期、成熟期,SRU3处理土壤线虫总数、食细菌线虫数量以及小麦成熟期SRU3处理的土壤捕食/杂食线虫数量显著高于U、SRU1和SRU2处理(p < 0.05);香农多样性指数(H′)、优势度指数(λ)表明小麦成熟期SRU3处理的物种多样性较高,且线虫群落组成较为均衡;脲酶抑制剂和硝化抑制剂组合型缓释尿素能够对土壤线虫群落结构产生有益的影响。

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试验采用室内模拟培养的方法,在不同用量脲酶/硝化抑制剂组合条件下,对辽宁省2种主要土壤—棕壤和褐土尿素氮转化的动态变化进行了研究。 结果表明,脲酶抑制剂N-丁基硫代磷酰三胺(NBPT)和苯基磷酰二胺(PPD)在施用量为尿素N量的0.05%时便有很好的脲酶活性抑制效果,且抑制效果随着脲酶抑制剂用量的增加而增强。NBPT和PPD在棕壤中的有效抑制时间为14天,在褐土中有效抑制时间为7天。两供试脲酶抑制剂相比,棕壤中PPD抑制效果好于NBPT,而在褐土中NBPT抑制效果好于PPD。 抑制剂组合各处理延缓了尿素的水解。土壤NH4+-N含量在前期较低,高峰值的出现延迟了2-6天;在培养中后期各抑制剂组合处理土壤NH4+-N含量显著提高。 抑制剂组合各处理土壤NO3--N含量在整个培养期均显著的降低。且在整个培养期间均显著降低了土壤NH4+的表观硝化率。在培养中后期,各处理能够增加棕壤有效氮含量;褐土中在第21天有效氮含量显著降低,而在第35天则有所回升。 试验表明,DMPP和DCD用量分别在施氮量的0.2%和0.25%时便可以达到很好的硝化抑制效果,且在棕壤中DCD的抑制效果好于DMPP,而在褐土中DMPP的抑制效果显著好于DCD

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土壤类型、温度等条件是影响硝化抑制剂效果的重要因素,为了探讨几种国外报道的高效硝化抑制剂在我国棕壤和红壤上的适应情况,以及温度等条件对于施肥土壤中NO3--N的积累和硝化抑制剂效果的影响,进行了本研究。采用室内培养的方式,研究了ATC、DMPP和CMP(每种抑制剂在两种土壤上分别设两个浓度处理)在我国棕壤和红壤上的效果,与目前应用较多的DCD(0.5%、1.0%两个浓度处理)进行效果对比;研究了温度条件、添加C源及培养条件对土壤中NO3--N积累及CMP硝化抑制效果的影响。结果表明,土壤条件是影响NO3--N积累和所用四种硝化抑制剂(DMPP、CMP、ATC、DCD)抑制效果的一个显著因素,棕壤中氮素转化较快,硝化抑制剂表现出效果较早,在红壤中起效时间较晚,在两种土壤条件下,所用抑制剂都表现出了良好的效果,在60天内ATC、CMP和DMPP的效果与10倍用量的DCD效果类似,甚至好于DCD,在棕壤中同种抑制剂的两个浓度处理之间存在显著差异,但是在红壤几个处理之间没有表现出显著差异;温度条件也是影响NO3--N积累的一个显著因素,从计算硝化抑制率看出,在25℃和30℃下CMP表现出了高效,37℃下抑制率下降,效果变差;添加两个浓度的葡萄糖对于对照中NO3--N的积累以及硝化抑制剂的硝化抑制效果没有表现出显著作用;增加的一步预培养恢复了土壤中微生物的活性在短期内体现了出来,但是长期看对于NO3--N积累量、变化趋势以及硝化抑制率都没有表现出显著作用。

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为利用双氰胺(DCD)减少N肥环境污染提供依据,室内试验和原位测定相结合,研究了不同情况下(土壤类型、双氰胺与氮肥结合形式、氮肥类型、土地利用方式)DCD对农田土壤痕量氮氧化物(N_2O和NO)排放及相关微生物过程的影响。结果显示:DCD对施肥土壤硝化过程有很强的抑制作用,提高NH_4~+浓度并使之保持较长时间,减少NO_3~-累积,减少N_2O和NO排放,间接促进肥料氮的固定和减少反硝化总损失,但可增加反硝化过程中产生的N_2O排放量。正常湿度条件下,DCD的硝化抑制作用和对NO与N_2O的减排作用受土壤粘粒与有机质含量影响较大。(源于硝化过程)的土壤NO排放量高于N_2O排队放量10倍以上。壤质土壤(粘粒含蓄量和有机质含量较低)中由施肥引起的NO和N_2O排队放量分别高于草甸棕壤的NO和N_2O排放量1倍左右。相同剂量的DCD,在壤质土壤中硝化抑制作用和对NO和N_2O的减排效果显著,在草甸棕壤中硝化抑制作用较小,虽然对NO和N_2O减排效果显著,但绝对值较小。开垦(17年)降低了草原土壤有机质含量,改变与N_2O排放相关的土壤氨化细菌和反硝化细菌的数量季节变化,加快了肥料N在土壤的转化速率,减少(施肥或不施肥)土壤N_2O排队放量,增强DCD的抑制作用。因施肥引起的N_2O排队放量较小,削弱了DCD对N_2O的减排作用。与混合态DCD相比,同碳酸氢铵形成的共结晶态DCD除了作为氨稳定剂减少氨挥发外,在促进肥料氮固定和硝化抑制方面稍弱(特别是在壤质土壤中),但对土壤NO和N_2O的减排队作用差异较小(对草甸棕壤NO排队放的影响例外,差异稍大)。长碳(DCD与碳酸氢铵的共结晶)和长尿(尿素+DCD+尿酶抑制剂+植物生长激素)减少施肥相起的氮氧化物排队放和硝酸盐累积,同时对作物有一定的增产作用。在推广长碳和长尿过程中,结合当地气候、土壤类型、营养状况,可达到提高作物产量,减少环境污染的双重目标。

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运用示踪尿素,以壤质草甸棕壤和春小麦分别作供试土壤和作物进行盆栽试验。结果表明,在试验结果时,植株和土壤对尿素氮的回收率及其损失分别占所施氮量17.65~23.69%,43.72~56.32%和19.99~36.77%。氢醌(HQ)和双氰胺(DCD)组合可使土壤、植株尿素氮回收率最高、损失量最低;而单施HQ或DCD均对比无明显影响。在小麦整个生育期内,该组合可增加小麦植株对肥料氮吸收;同时促进茎秆中氮向籽实转移。配施抑制剂时,土壤有机氮占肥料氮回收率相当大的比例,小麦成熟期时可达34.31~51.80%,而单施尿素处理只有9.83%;DCD及其与HQ组合可有效地保持尿素水解后土吉氨态氮含量,并显著降低土中氧化态氮的富集。因此,配施抑制剂,尤其是HQ+DCD,有利于尿素施放后土壤持续有效地保持肥粒氮量。大氮素损失方面,N_2O只占较小的比例;主要部分为NH_3挥发损失。DCD,尤其与HQ组合,可延迟尿纱施入后土壤-小麦系统中N_2O排放高峰的出现,并降低小麦整个生育期内该系统中N_2O排放总量和NH_3挥发量,尤其是后者。配施抑制剂,尤其是DCD及其与HQ组合,可明显促进稻株地上部分生长,制约水稻拔节期前根际内土中尿素水解后无机氮行为;显著提高尿素施入后稻田系统中水-土和根-土界面CH_4氧化潜势,尤其大水稻分蘖-拔节期。表施有机物料可显著削弱上述抑制剂的促进作用。未施有机物料时,配施抑制剂,尤其是DCD及其与HQ组合可显著降低稻株地上部分NO_3~--N含量。其含量与土壤-水稻系统中N_2O排放量呈显著指数正相关;同时无明显稻株释放N_2O,而单施尿素处理却较高,占尿素氮量0.47 ± 0.08%。表施麦秸粉时,HQ+DCD可显著降低土壤和土壤-水稻系统中N_2O排放量;单施尿素处理水稻植株释放N_2O约占尿素氮量1.28 ± 0.18%,而配施DCD-HQ却显著降低,只为0.66 ± 0.08%。回归分析表明,土-水界面土壤中NO_3~--N的反硝化作用是稻田系统中N_2O排放的主要来源,尤其在表施有机物料时。我们研究显示:稻田系统中N_2O和CH_4排放量呈显著对数负相关关系;表施有机物料时,两者虽互为消长关系,但很难定量化。

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采用室内培养和田间小区实验相结合的方法,研究了硫脲(TU,0.1%,0.3%,0.5%,1.0%,5.0%)不同浓度以及TU和硝化抑制剂双氰胺(DCD)、脲酶抑制剂苯基磷酞二胺(PPD)组合对土壤脲酶活性、土壤尿素氮转化和玉米产量的影响。室内培养试验表明,硫脲既是一种弱脲酶抑制剂又是一种硝化抑制剂。硫脉对脲酶活性和尿素水解均有显著的抑制作用,但是作用时间较短;硫脉用量为0.1%时,就起到了抑制作用,用量0.3%-1.0%之间差异不显著,用量1.0%-5.0%之间抑制效果随用量增加而加强。硫脉不同用量对土壤NH_4~+-N释放和向NO_3~--N的进一步转化有明显的抑制作用,作用强度随抑制剂用量增加而增强。硫脲不仅仅延缓了土壤NH_4~+-N的释放高峰期一周,而且降低了土壤中NO_3-N的富集,使NO_3~--N的释放高峰期向后推迟了10天。本试验条件下,土壤中的NH_4~+-N向NO3--N转化的时间大约为7~10天;土壤中有效氮的含量主要取决于土壤NH4+-N的含量,受NO3-N含量的影响次之。田间模拟培养表明,硫脲及其抑制剂组合对土壤脲酶活性有显著的抑制作用,抑制时间为2周,其中抑制剂组合TU_1+PPD对脲酶活性的抑制作用持续了65天。TU、TUI+DCD和TUI+PPD,对土壤NH_4~--N的释放有显著的抑制作用,对NH_4~+-N向NO_3~--N的进一步转化有显著的抑制作用,进而影响土壤有效氮的总量。总的来看,硫脲及抑制剂组合的抑制效果,依次是TU_1+P PD>TUI+DCD>TU_2>TU_1。硫服及抑制剂组合对玉米株高、百粒重和产量的影响基本是一致的,TU和抑制剂组合Tul十PPD、TU1+DCD的作用效果显著优于单施尿素,处理之间差异不显著。施用抑制剂显著增加了玉米产量,增产幅度为9.14%~11.49%。